cDNA clones encoding antimicrobial guinea pig neutrophil cationic peptides GNCP-1 and GNCP-2 were isolated from a bone marrow cell cDNA library. Analysis of these clones indicated that both GNCPs were produced as precursor proteins comprising 93 amino acid residues, which were composed of signal sequences (N-terminal 19 residues), pro-peptide sequences (43 residues) and mature GNCP sequences (31 residues). The deduced amino acid sequence showed that there were only two amino acid differences between GNCP-1 and GNCP-2, one in the pro-peptide region and one in the mature peptide region. Interestingly, Northern blot analysis and transcription run-off assay revealed that the expression of GNCP mRNA and the transcription of GNCP gene was observed in bone marrow cells but not in mature neutrophils. These observations suggest that mature neutropils, despite their abundant content of GNCPs, lose the capacity to synthesize GNCPs.
